1. Field of the Invention
This invention relates to bicycle crankshaft assemblies designed to be light in weight while maintaining good structural strength and stiffness, with cost effective manufacturing and at reasonable cost, while permitting simple assembly and installation.
2. Description of the Prior Art
In recent years bicycles have made a significant comeback and are used extensively by a large number of people both for pleasure and in competition.
It is highly desirable to make the bicycle lighter in weight while at the same time achieving good structural strength. This provides the user with a considerable advantage, especially in a competitive situation.
A common part of the bicycle is the crankshaft assembly which includes a central crank axle and crank arms affixed to the outer ends of the crank axle. Connected to the outer ends of each crank arm is the bicycle pedal which is used by the rider to apply motive force to the bicycle.
It is naturally highly desirable to provide a strong, light weight crank shaft assembly, but this is difficult to accomplish in view of the large amount of stress placed on the assembly with repeated cyclic loading.
Efforts have been made to provide such strong, light weight crankshaft assemblies, such as in the following U.S. Pat. Nos. 4,811,626, 5,010,785, 2,350,468, 602,049, 4,704,919, 4,171,822, 3,906,811 and 5,493,937.
However, these have one or more shortcomings.
It is, therefore, desirable to provide an improved crankshaft assembly having light weight while maintaining good structural strength and stiffness.